Methods: 2.0 mm thick dentine disks were cut from human third molars parallel to the occlusal surface and perfused with Earle's solution. The smear layer was removed with 10% citric acid. The bottom and sides of each disk were masked with polyethylene tape exposing tubules from the top surface only. Thereafter disks were mounted in plastic syringes filled with Earle's solution. The disks were immersed in 0.5M caesium acetate solution for 2.5h to identify the baseline diffusion profile for the disk. Caesium acetate was then purged from the disks by immersion in water. Treatments were applied to the exposed surface and the disks were re-immersed in caesium acetate solution for 2.5h. XMT scans (15µm resolution) were taken at each stage to compare changes in X-ray attenuation due to the ingress of caesium acetate into dentine before and after each treatment.
Results: XMT images showed that ingress of caesium acetate was substantially reduced following treatment with bonding agent.
Conclusion: The application of a resin bonding agent significantly reduced the ingress of caesium acetate, presumably through the action of tubule occlusion. XMT can be used to monitor ion diffusion in dentine, which allows the investigation of occlusion based treatments for dentine hypersensitivity.
This work was supported via a GSK funded CASE studentship and Institute of Dentistry, QMUL.